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Wording tweaks
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@ -144,11 +144,11 @@ Or, to put it in English, we might say:
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> Our solution, $S$, is the union of all sets produced by applying each function, $F_i$,
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> to points in the solution.
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There's just one small problem: to find the solution, we must apply these functions to points
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we know are in the solution. But how do we know which points are in the solution to start with?
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There's just one small problem: to find the solution, we must already know which points are in the solution.
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What?
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John E. Hutchinson provides an answer in the [original paper](https://maths-people.anu.edu.au/~john/Assets/Research%20Papers/fractals_self-similarity.pdf)
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explaining the mathematics of iterated function systems:
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John E. Hutchinson provides an explanation in the [original paper](https://maths-people.anu.edu.au/~john/Assets/Research%20Papers/fractals_self-similarity.pdf)
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defining the mathematics of iterated function systems:
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> Furthermore, $S$ is compact and is the closure of the set of fixed points $s_{i_1...i_p}$
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> of finite compositions $F_{i_1...i_p}$ of members of $F$.
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@ -159,7 +159,7 @@ I've tweaked the conventions of that paper slightly to match the Fractal Flame p
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Before your eyes glaze over, let's unpack this:
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- **$S$ is [compact](https://en.wikipedia.org/wiki/Compact_space)...**: All points in our solution will be in a finite range
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- **Furthermore, $S$ is [compact](https://en.wikipedia.org/wiki/Compact_space)...**: All points in our solution will be in a finite range
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- **...and is the [closure](https://en.wikipedia.org/wiki/Closure_(mathematics)) of the set of [fixed points](https://en.wikipedia.org/wiki/Fixed_point_(mathematics))**:
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Applying our functions to points in the solution will give us other points that are in the solution
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- **...of finite compositions $F_{i_1...i_p}$ of members of $F$**: By composing our functions (that is,
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@ -188,7 +188,7 @@ This is still a bit vague, so let's work through an example.
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## [Sierpinski's gasket](https://www.britannica.com/biography/Waclaw-Sierpinski)
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The Fractal Flame paper gives us three functions to use for our first IFS:
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The Fractal Flame paper gives three functions to use for a first IFS:
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$$
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F_0(x, y) = \left({x \over 2}, {y \over 2} \right) \\
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@ -200,8 +200,8 @@ $$
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### The chaos game
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Next, how do we find the "fixed points" we mentioned earlier? The paper lays out an algorithm called the "[chaos game](https://en.wikipedia.org/wiki/Chaos_game)"
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that gives us points in the solution set:
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Next, how do we find the "fixed points" mentioned earlier? The paper lays out an algorithm called the "[chaos game](https://en.wikipedia.org/wiki/Chaos_game)"
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that gives us points in the solution:
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$$
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\begin{align*}
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@ -218,7 +218,7 @@ $$
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The chaos game algorithm is effectively the "finite compositions of $F_{i_1..i_p}$" mentioned earlier.
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:::
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Now, let's turn this into code, one piece at a time.
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Let's turn this into code, one piece at a time.
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First, we need to generate some random numbers. The "bi-unit square" is the range $[-1, 1]$,
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so we generate a random point using an existing API:
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